Field of the Invention
The present invention relates to a medical diagnostic imaging system including an X-ray imaging apparatus provided with a Talbot interferometer or a Talbot-Lau interferometer to generate a plurality of types of medical diagnostic images.
Description of Related Art
A variety of flat panel detectors (FPDs, or radiographic imaging devices) have been developed which include a two-dimensional array of conversion elements to generate an electrical signal according to X-rays emitted from an X-ray source and passing through a subject, and read the generated electrical signal as image data. These flat panel detectors have been used for generation of medical diagnostic images (in this case, X-ray absorption images) in medical practice such as hospitals. A variety of medical diagnostic imaging systems have also been developed which include FPDs, X-ray sources, and consoles.
In many medical diagnostic imaging systems, medical diagnostic images formed by the image processing apparatus (or a console serving as an image processing apparatus) from image data obtained with an FPD are output to external systems or devices (e.g., a picture archiving and communication system (PACS)) in an order appropriate for visual convenience for radiographic interpreters instead of the shoot order (see WO2011/142157, for example).
In recent years, X-ray imaging apparatuses have also been developed which are provided with Talbot interferometers or Talbot-Lau interferometers including FPDs, X-ray sources irradiating FPDs with X-rays, and a plurality of gratings (see Japanese Unexamined Patent Application Publication No. 2008-200359 and WO 2011/033798, for example). An X-ray imaging apparatus provided with a Talbot interferometer or Talbot-Lau interferometer is hereinafter referred to as “X-ray Talbot imaging apparatus”. An FPD in an X-ray Talbot imaging apparatus is hereinafter referred to as an “X-ray detector” as distinguished from an FPD for normal photography, but has the same basic structure as the FPD. The FPD and X-ray detector both have a two-dimensional array of conversion elements to generate an electrical signal according to the incident X-rays.
In the X-ray Talbot imaging apparatus, the X-ray detector detects X-rays emitted from the X-ray source and passing through the subject and the gratings and reads the electrical signal generated by the conversion elements as moire image(s). The image processing apparatus reconstructs the moire image(s) into a plurality of types of medical diagnostic images, such as an absorption image, a differential phase image, and a small-angle scattering image. The reconstruction into such a plurality of types of medical diagnostic images typically requires fringe scanning or the Fourier transform.
In the case of the Fringe scanning, the X-ray Talbot imaging apparatus makes two or more X-ray exposures while moving the gratings relative to each other in order to generate two or more moire images. The image processing apparatus then reconstructs the moire image(s) into a plurality of types of medical diagnostic images, such as an absorption image, a differential phase image, and a small-angle scattering image. In the case of the Fourier transform, the X-ray Talbot imaging apparatus makes a single X-ray exposure to generate a single moire image. The image processing apparatus then analyzes and reconstructs the single moire image into a plurality of types of medical diagnostic images, such as an absorption image, a differential phase image, and a small-angle scattering image.
The medical diagnostic images (e.g., an absorption image, a differential phase image, and a small-angle scattering image) generated by both approaches show the subject in the same position because they are all reconstructed from the same moire image(s) obtained by radiographing the subject. That is, these images show the same part of the subject at the same pixel position. The medical diagnostic images show the same subject in different contrasts etc.
As in normal photography, the X-ray Talbot imaging apparatus generates one or more moire images by one or more exposures of the subject to X-rays, and the image processing apparatus reconstructs the moire image(s) into medical diagnostic images (e.g., an absorption image, a differential phase image, and a small-angle scattering image) and then may immediately output the medical diagnostic images to external systems or devices (e.g., a PACS).
The image processing apparatus does not always output such medical diagnostic images to external systems or devices immediately after the generation. In some cases, for instance, radiography is performed for the same patient's two or more parts or two or more patients, the image processing apparatus repeats reconstruction into medical diagnostic images after completion of all the radiographic processes, and then collectively outputs the medical diagnostic images to external systems or devices (e.g., a PACS).
In the latter case, if the medical diagnostic images are collectively output to external systems or devices in an order appropriate for visual convenience for radiographic interpreters as described above, the medical diagnostic images (e.g., an absorption image, a differential phase image, and a small-angle scattering image) belonging to one group based on the moire image(s) of the same part of the same patient may be output separately, mixed into medical diagnostic images of another patient, or partially lost.
This may cause a situation where a radiographic interpreter fails to interpret patient's medical diagnostic images by lack of any of the diagnostic images; cause misdiagnosis announcing the presence of a lesion in a wrong patient due to the confusion of medical diagnostic images; and cause misdiagnosis announcing the absence of a lesion in a patient who actually has the lesion.